src: add Cleanable class to Environment

We store a linked list of `Cleanable` objects on the
`node::Environment` and invoke their `Clean()` method during env
teardown. `Cleanable`s can be added/removed using
`Environment::AddCleanable()` resp. `Environment::RemoveCleanable()`.

This eliminates the need for adding many cleanup hooks.

Author: gabrielschulhof

src/env.cc

@@ -1279,6 +1279,11 @@ void Environment::RunCleanup() {
   // Defer the BaseObject cleanup after handles are cleaned up.
   CleanupHandles();
 
+  while (!cleanable_queue_.IsEmpty()) {
+    Cleanable* cleanable = cleanable_queue_.PopFront();
+    cleanable->Clean();
+  }
+
   while (!cleanup_queue_.empty() || principal_realm_->HasCleanupHooks() ||
          native_immediates_.size() > 0 ||
          native_immediates_threadsafe_.size() > 0 ||

src/env.h

@@ -594,6 +594,18 @@ void DefaultProcessExitHandlerInternal(Environment* env, ExitCode exit_code);
 v8::Maybe<ExitCode> SpinEventLoopInternal(Environment* env);
 v8::Maybe<ExitCode> EmitProcessExitInternal(Environment* env);
 
+class Cleanable {
+ public:
+  virtual void Clean() = 0;
+  virtual ~Cleanable() = default;
+
+ protected:
+  ListNode<Cleanable> cleanable_queue_;
+
+ private:
+  friend class Environment;
+};
+
 /**
  * Environment is a per-isolate data structure that represents an execution
  * environment. Each environment has a principal realm. An environment can
@@ -902,8 +914,10 @@ class Environment final : public MemoryRetainer {
 
   typedef ListHead<HandleWrap, &HandleWrap::handle_wrap_queue_> HandleWrapQueue;
   typedef ListHead<ReqWrapBase, &ReqWrapBase::req_wrap_queue_> ReqWrapQueue;
+  typedef ListHead<Cleanable, &Cleanable::cleanable_queue_> CleanableQueue;
 
   inline HandleWrapQueue* handle_wrap_queue() { return &handle_wrap_queue_; }
+  inline CleanableQueue* cleanable_queue() { return &cleanable_queue_; }
   inline ReqWrapQueue* req_wrap_queue() { return &req_wrap_queue_; }
 
   // https://w3c.github.io/hr-time/#dfn-time-origin
@@ -1192,6 +1206,7 @@ class Environment final : public MemoryRetainer {
   // memory are predictable. For more information please refer to
   // `doc/contributing/node-postmortem-support.md`
   friend int GenDebugSymbols();
+  CleanableQueue cleanable_queue_;
   HandleWrapQueue handle_wrap_queue_;
   ReqWrapQueue req_wrap_queue_;
   std::list<HandleCleanup> handle_cleanup_queue_;

src/node_buffer.cc

@@ -84,7 +84,7 @@ using v8::Value;
 
 namespace {
 
-class CallbackInfo {
+class CallbackInfo : public Cleanable {
  public:
   static inline Local<ArrayBuffer> CreateTrackedArrayBuffer(
       Environment* env,
@@ -95,9 +95,9 @@ class CallbackInfo {
 
   CallbackInfo(const CallbackInfo&) = delete;
   CallbackInfo& operator=(const CallbackInfo&) = delete;
+  void Clean();
 
  private:
-  static void CleanupHook(void* data);
   inline void OnBackingStoreFree();
   inline void CallAndResetCallback();
   inline CallbackInfo(Environment* env,
@@ -112,7 +112,6 @@ class CallbackInfo {
   Environment* const env_;
 };
 
-
 Local<ArrayBuffer> CallbackInfo::CreateTrackedArrayBuffer(
     Environment* env,
     char* data,
@@ -152,25 +151,23 @@ CallbackInfo::CallbackInfo(Environment* env,
       data_(data),
       hint_(hint),
       env_(env) {
-  env->AddCleanupHook(CleanupHook, this);
+  env->cleanable_queue()->PushFront(this);
   env->isolate()->AdjustAmountOfExternalAllocatedMemory(sizeof(*this));
 }
 
-void CallbackInfo::CleanupHook(void* data) {
-  CallbackInfo* self = static_cast<CallbackInfo*>(data);
-
+void CallbackInfo::Clean() {
   {
-    HandleScope handle_scope(self->env_->isolate());
-    Local<ArrayBuffer> ab = self->persistent_.Get(self->env_->isolate());
+    HandleScope handle_scope(env_->isolate());
+    Local<ArrayBuffer> ab = persistent_.Get(env_->isolate());
     if (!ab.IsEmpty() && ab->IsDetachable()) {
       ab->Detach(Local<Value>()).Check();
-      self->persistent_.Reset();
+      persistent_.Reset();
     }
   }
 
   // Call the callback in this case, but don't delete `this` yet because the
   // BackingStore deleter callback will do so later.
-  self->CallAndResetCallback();
+  CallAndResetCallback();
 }
 
 void CallbackInfo::CallAndResetCallback() {
@@ -182,7 +179,7 @@ void CallbackInfo::CallAndResetCallback() {
   }
   if (callback != nullptr) {
     // Clean up all Environment-related state and run the callback.
-    env_->RemoveCleanupHook(CleanupHook, this);
+    cleanable_queue_.Remove();
     int64_t change_in_bytes = -static_cast<int64_t>(sizeof(*this));
     env_->isolate()->AdjustAmountOfExternalAllocatedMemory(change_in_bytes);